A rocket-propelled grenade whooshes down a New York street, leaving a twirling vapour trail in its wake. Its target is a speedily incoming police car, its source is… you.

Grand Theft Auto is back, and if you didn't queue outside your local game shop to get your hands on it tonight you probably know someone who did – it's just that they might not have told you. Or, indeed, anyone.

While many saw the release of the fair-minded Byron Report as a benchmark moment in the relationship between violent videogames and mainstream moral thought, this is the real litmus test. This is where we find out how far games have crossed into the mass consciousness. You see, while the latest title in Rockstar's gangster adventure series is forecast to make $400m in its opening week, it's still amazing how few people seem to understand what the games are about – or how slyly clever they are.

And that goes not just for the tabloids and their readers, but for the industry itself. Following the huge success and cultural impact of GTA Vice City in 2002, almost every major videogame publisher hastily commissioned their own 'gangsta' series. At the E3 exhibition in 2005 there were almost a dozen on show with names like True Crime: New York, Crime Life: Gang Wars, Fear and Respect and Final Fight: Street Wise.

True Crime: clones failed to understand GTA's subtler touch
Most of them bombed. One – Midway's Fear and Respect - was canned before it even assaulted the shelves, despite boasting the collaboration of Boyz N The Hood director John Singleton. Saint's Row is the only wannabe still touting its simplified gangland fare, with a sequel due out later this year.

None of the titles caught on to the subtleties of the GTA franchise. Beneath the ramrod violence this is a deeply satirical series, lampooning machismo brutality more than celebrating it. In GTA IV, for example, you're not dealing with criminal masterminds or cool gangland alpha males, you're sloshing around in the cesspit of low-level criminal culture. One of the most exciting early missions is a bank heist with three Irish brothers who bicker incessantly throughout the build-up and into the disastrous robbery itself. There are suggestions at least one has IRA affiliations but the script hints at the truth – it's all bluster and self-mythologising.

You'll also need to carry out a hit for a character named Brucie, a tracksuit wearing medallion man who runs a garage and fantasies about performing the assassination himself. His tough guy demeanor is quickly spiked in a funny cut-scene where he attempts to play wrestle with Niko and is humiliated when the lead character blocks his moves and forces him to his knees.

The game continually jabs at macho posturing – "war is where the young and stupid are manipulated into killing each other by the old and bitter", says one character when he learns of Niko's military past - a sly dig at the prevalent culture of celebratory shooters like Call of Duty and Medal of Honor. Videogame scripts don't often as a rule, hint at anything, let alone the vacuity of heroism.

Not just enemies

GTA IV also has new things to say about kinship in videogames. In other gangster titles, you'll need to build an army of faceless hoods to perform your drive-by bidding. Here, you must forge and maintain friendships – no missions are earned from strangers, and everyone you work for is personally introduced by a colleague. Your progress through the game is dictated not just by your actions with a machine gun, but through a spider's web of poisonous associations.

Whenever you meet a character, their name goes into the contacts book of your in-game mobile phone. When you feel like it you can take your handset out and call someone, anyone, and invite them to a pool hall, to a comedy club or strip bar – whatever you reckon takes their fancy. In this way, slowly, but surely, you earn their trust and their friendship; get it right and they'll do favours for you, providing everything from free cabs to new weapons.

But there are moments you'll let them down; a friend in need may call while you're in the middle of a tricky mission and so you ignore it, only to find out they've been kidnapped… or worse. Of course, the examination of touching relationships within the criminal fold is nothing new to TV or film, but its odd indeed for a videogame to reference Donny Brasco and The Wire rather than the latest high concept shoot fest or sci-fi SFX blow-out.

Niko: a Vito Corleone for the 21st century
It is also one of the few games to have presented sex and relationships with such candour. Through its cast of hookers and miscreants, Vice City reveled in the misogynistic excesses of its inspirations, Scarface and Miami Vice; San Andreas toyed with a daft interactive sex scene that prompted the ridiculously frenzied 'hot coffee' scandal - and the scorn of Hillary Clinton. In GTA IV, you meet women (or men) only through an internet dating site on the game's own version of the web. Here, as in modern life, relationships are virtualised through mobiles and online social networks.

At the heart of it all, there is a modern interpretation of the American Dream as immigrant experience. Lead character Niko Bellic is a Serbian national with a violent military past who arrives in Liberty City via a rusted container ship. He is the archetypal outsider, striving to start a new life in the Land of the Free; a Vito Corleone for the 21st century. There are also themes of ethnicity, race and identity in contemporary America, of heritage and culture, of the struggle to fit in. When Niko arrives, he's quickly forced to assimilate into an Eastern European criminal underworld. For him, there is no escape from the old life, the old country.

Of course, all this stuff lurks in the background and doesn't have to interfere with the anarchic action. Plenty of people might play the game without ever realising its true complexity - but it might give you something to think about the next time you launch an RPG down a crowded Liberty City street.